The purpose of this study is to define the genetic and biochemical basis of a naturally occurring disease in the dog, which is characterized by recurrent pyogenic infections resulting from defective intraneutrophilic microbicidal capacity. A series of studies will be conducted which are designed to provide a basis of comparison between this and other related human and animal diseases. The proposed studies are modeled after those which have been used to delineate the structure, metabolic, and functional abnormalities in human neutrophil dysfunction syndromes. Preliminary studies suggest that this disease which we have referred to as canine granulocytopathy syndrome (CGS) is similar to, but not homologous with any other documented human or animal host defense failure syndrome. The unique nature of this spontaneously occurring disease could make it a very valuable research resource. The use of the CGS as a model of neutrophil dysfunction syndromes provides previously unavailable opportunities for assessing the relative role of factors involved in the microbicidal event. It is anticipated that these investigations will contribute to the understanding of the processes and mechanisms involved in the post-phagocytic handling of pathogens by neutrophils and could therefore make a valuable contribution to basic biomedical research.